I wanted to share this note from Jack Daniels, because a number of runners now at the World Masters Track and Field Championships (Kamloops) have written me, saying that their times are slower than anticipated…..they wondered whether the 1100 feet of altitude there might have affected performance if they have been training at sea level. I wasn’t sure, but found this note from Jack Daniels which I wanted to share. The bottom line is that, yes, altitude could have affected the longer races in particular and those in the older age categories.

Here is Daniels’ note:

“Performance starts to be affected at about 1,000 meters altitude; the effect is not linear and the drop in performance is quite different for acclimated versus unacclimated individuals. A runner who is not acclimated will lose 10 to 12% in VO2max at an altitude of about 6,500 feet and 12 to 15% at 7,500 feet. However, performance will not be to the same degree because running economy is better at altitude (due to the less dense air resistance). Our research at 6,500 feet indicated a 12% loss of VO2max, but 6% improvement in running economy resulting in 6% loss in performance. The duration of a race is also a factor. An 800-meter race is so anaerobic that little performance difference exists. A 1,500-meter race may be six to 10 seconds slower, but over 20 seconds slower for unacclimated runners. An unacclimated runner could expect to lose a minute in 5K and as much as two minutes for a 10K.”